1. Field of the Invention
This invention relates to the art of light emitting devices, and more particularly to a light emitting device which will be suitable for use in optical communication and optical measurement. The light emitting device in accordance with the present invention includes semiconductor lasers and various light emitting diodes.
2. Description of the Prior Art
It is well known that when Zn, Ga or Si is diffused or ion-implanted locally into a multiple layer ultra-thin film made of InAlAs having different compositions and is then heat-treated, the constituent elements cause mutual migration due to the diffusion of the additive element and a film having a uniform composition on an average can be obtained. This is referred to as "disordering" by diffusion. A light emitting device having a structure wherein optical distribution is confined by use of the difference of refractive indices between the multiple layer film portion and the portion having the uniform composition by utilizing the disordering described above has been reported. Refer, for example, to Appln. Phys. Letts. 45 (1984), pp. 1-3. This is an effective method of accomplishing a refractive index confinement structure by a planar process such as diffusion and ion implantation.
In an optical communication system, a light emitting device having a wavelength ranging from 1.1 to 1.6 .mu.m is of particular importance, but it is not easy to cause disordering by use of an InGaAsP system material that has been widely utilized in this wavelength band. Therefore, there arose the problem that confinement of optical distribution by utilizing disordering cannot be realized by use of the 1.1-1.6 .mu.m wavelength band.